There has been widespread use of optical disc apparatuses that record and reproduce information in and from disc-shaped optical discs such as CDs (Compact Discs), DVDs (Digital Versatile Discs), and Blu-ray Discs® (hereinafter, “BD”).
Such optical disc apparatuses use an optical disc to record various types of information, including content such as music content and video content, and various forms of computer data.
The recent development for higher resolution videos and higher sound quality for music has increased the amount of information, and thus the volume of content for recording in a single optical disc. Accordingly, there is a demand for larger-capacity optical discs.
In one proposed approach to increase the capacity of the optical disc, the recording pits as the representation of information are arranged three-dimensionally using a two-photon absorption reaction for their formation (see, for example, Patent Document 1).
Prior Art Documents
Patent Document 1: JP-A-2005-37658
Patent Document 2: JP-A-2008-71433